1. Field of the Invention
The present invention relates to a display driver that drives a display device in response to a video signal.
2. Background Art
In display devices such as liquid crystal display panels, a plurality of gate lines extending in a horizontal direction on a two-dimensional screen and a plurality of source lines extending in a vertical direction on the two-dimensional screen are arranged so as to intersect with each other. The display panels further incorporate a source driver and a gate driver. The source driver applies gradation display voltages to the respective source lines, the gradation display voltages corresponding to the luminance levels of respective pixels represented by an input video signal. The gate driver applies a scanning signal to the gate lines. As such a source driver, there is proposed a device configured to individually capture a plurality of pieces of display data for one horizontal synchronization period into each of a plurality of latches and to apply gradation display voltages to the respective source lines, the gradation display voltages corresponding to the display data captured into the respective latches (see, for example, Japanese Patent Application Laid-Open No. 2004-301946). In this source driver, the above-stated latches each capture the display data at the timing shifted by a delay circuit which uses a delay of inverter elements. With this configuration, the source driver avoids the situation of steep and simultaneous change in currents that flow into the respective source lines and thereby prevents noise generated in such a situation.
However, in the delay circuit as described in the foregoing, the delay amount is fixed in advance, and the delay amount itself is changed by manufacturing variations, environmental temperature, and the like. This makes it difficult for the driver to adapt to the specifications of various display devices.